Counting chain



July 30,

G. R. PAUL COUNTING CHAIN Filed June 25, 1954 INVENTOR. GERALD R. PAUL HIS AGENT United States Patent COUNTING CHAIN Gerald R. Paul, Rochester, N. Y., assignor, by mesne assignments, to General Dynamics Corporation, a corporation of Delaware Application June 23, 1954, Serial No. 438,836

4 Claims. (Cl. 315-845) My invention relates to counting chains, and more particularly to counting chains of the type using gaseous discharge devices. 7

Gas tube counting chains used before my invention have employed individual coupling capacitors from the source of pulses to be counted to the governing electrodes,

o r start electrodes as they are sometimes known, of the tubes in the chain. This has required a multiplicity of capacitors. Furthermore, such chains have proved erratic in operation when input pulses of excessive amplitude are received.

It is an object of my invention to provide a counting chain which has a new and advantageous configuration.

It is also an object of my invention to provide a counting chain which is reliable in operation, yet which uses a minimum number of components.

It is a further object of my invention to provide a counting chain which is relatively unaffected by excessive amplitude of pulses to be counted.

In general, I accomplish the foregoing and other objects of my invention by connecting the anodes of the discharge devices in parallel; anode load means are con nected in series between these anodes and a suitable source of operating potential for the discharge devices. The source of pulses to be counted is connected to the parallel connection of the anodes of the discharge devices. With this arrangement, I am able to achieve a stepping of a conductive condition from discharge device to discharge device along the cascade connection, thereby providing the familiar counting action of a counting chain.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawing, which shows a schematic circuit diagram of a preferred embodiment of my invention.

Referring now to the drawing, there is shown a counting chain including a plurality of discharge tubes 1 which are preferably of the cold cathode gaseous discharge type. Each of the discharge devices has an anode 2, a cathode 3 and a governing, or start, electrode 4. Anodes 2 are connected in parallel.

There is provided a suitable source of operating potential for anodes 2, such as battery 5. Anode load means 6, preferably resistive in character as shown, is connected in series between the parallel connection of anodes 2 and the source of operating potential 5. Each discharge tube 1 is provided with a cathode load resistor 7 which is partially bypassed by suitable means, such as capacitor 8. The cathode 3 of each stage other than the last is coupled to the governing electrode 4 of the succeeding stage through a resistor 9 connected in series between the cathode of the preceding stage and the governing electrode. Resistor 9 is preferably by- 2,801,370 Patented July so, 1957 chain having three stages but those skilled in the art can readily appreciate that any other number of tubes may be interconnected in the manner illustrated, depending upon the desired counting base. Most commonly, this base is 10, in order to provide a decimal counting chain. I have employed dashed lines in the drawing to indicate how the chain may be extended in accordance with my invention.

Throughout this specification, the conventional ground symbol is used to indicate connection to a plane of reference potential, such as zero potential. This connection may be to a chassis, for example, or to earth.

There are also provided, in the illustrated embodiment of my invention, means for priming the first gaseous discharge device. This priming means is connected to the governing electrode of the first such discharge device, and may include switch means 11 and a suitable source of potential, such as battery 12. Also shown in the drawing is a suitable source 13 of positive-going pulses to be counted. This source is preferably connected to the parallel connection of anodes 2 through a series capacitor 14 as shown.

In operation, switch 11 may be. momentarily closed to prime the first tube of the chain through the application of a positive potential from battery 12 to the governing electrode 4, of the first discharge device in the chain. This establishes conduction within the first stage.

Under this condition, the conduction current of the first stage causes a voltage drop through its cathode resistor 7. The resulting positive potential appears, by reason of the D.-C. coupling between stages through series resistor 9, on the governing electrode 4 of the succeeding stage. Though this potential is positive, its magnitude is insufiicient to cause conduction within the second stage.

When the first pulse to be counted is received from source 13 at the anode of the first gaseous discharge device in the chain, the potential at cathode 3 of this discharge device rises because of the constant-voltage-drop characteristic of the gaseous discharge device. This rise of potential is conducted, partly through series resistor 9 but principally through capacitor 10 to the governing electrode 4 of the succeeding discharge device, thereby igniting the latter. The ignition process is assisted by the fact that capacitor 8 of the second stage cannot charge instantaneously, and therefore momentarily assures maximum potential difference between cathode 3 and anode 2.

Meanwhile, capacitor 8 of the first stage, being a partial bypass means, cannot discharge immediately, and therefore tends to maintain the potential of the cathode 3 of the first stage high. But the potential available to its anode 2 drops because of the additional current drawn through the anode load means 6 by the second discharge device of the chain, together with the charging current of its cathode capacitor 8. The potential between anode 2 and cathode 3 is thus lowered until the conduction condition within the first stage can no longer be maintained. Thus, it may be seen that the first pulse to be counted has transferred the conductive condition of the first, or prime, discharge device to the second, or count 1, discharge device.

Receipt of a second pulse to be counted from pulse source 13 causes a stepping of the conductive condition from the second to the third discharge device in the eascade connection, by reason of the same action between the second and third discharge devices as was described above relative to the first and second. Further stepping action occurs through as many successive discharge de tions will readily occur to those skilled in "the art.

vices as are provided in the counting chain, a step being taken as each pulse is received from pulse source 13.

While I have shown and described my invention as applied to a specific embodiment thereof, other modifica- -I do not, therefore, desire my invention to be limited to the specific arrangement shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim is:

1. In a counting chain, the combination of a plurality of gaseous discharge devices connected in cascade, each said discharge device having an anode, a cathode, and a governing electrode; means connected to saidgoverning electrode of the first of said gaseous discharge devices for the priming thereof; means for coupling the cathode of each said discharge device, other than the last, to the governing electrode of the succeeding said discharge device, said anodes of said gaseous discharge devices being connected in parallel; a source of operating potential for said discharge device; anode load means connected in series between said anodes and said source of operating potential; and a source of pulses to be counted, said pulse source being connected to said parallel connection of said anodes, whereby each pulse received from said pulse source after priming is effective to step a conductive condition from discharge device to discharge device along said cascade connection.

2. The combination of claim 1 in which said anode load means comprises a resistance.

3. The combination of claim 1 in which the pulses from said pulse source are positive-going, thereby adding their amplitude to that of the potential at said anodes due to said source of operating potential.

4. The combination of claim 1 in which said cathode coupling means includes a cathode load resistor, partial bypass means for said cathode load resistor, and resistance means connected in series between said cathode and said governing electrode of the succeeding said discharge device.

References Cited in the file of this patent UNITED STATES PATENTS 2,404,918 Overbeck July 30, 1946 2,515,448 Gulden July 18, 1950 2,556,704 Parkinson June 12, 1951 FOREIGN PATENTS 677,872 Great Britain Aug. 20, 1950 

